C1ORF54在小鼠心肌梗死后心脏修复中的作用

目的:探讨1号染色体开放读码框54位基因编码蛋白(C1ORF54)在小鼠心肌梗死后心脏修复中的作用及其机制。方法:选择C1ORF54基因敲除小鼠与野生型小鼠,采用结扎冠状动脉左前降支制作心肌梗死小鼠模型。21 d后以超声心动图测定各组小鼠心功能相关指标,Masson染色法观察心脏组织纤维化程度。应用免疫组织化学染色法检测心肌梗死后第3天心脏Ki-67蛋白表达变化;应用Western blot定量测定各组小鼠p38丝裂原活化蛋白激酶/磷酸化的p38丝裂原活化蛋白激酶(p38/p-P38)、信号转导及转录激活因子3/磷酸化的信号转导及转录激活因子3(STAT3/p-STAT3)、β-连环蛋白(β-catenin)和磷酸化蛋白激酶B(p-AKT)等的表达水平。结果:心肌梗死21 d后,尽管两组小鼠的心率相似,但与野生型小鼠相比,C1ORF54基因敲除小鼠左室舒张末期内径[(6.04±0.14)mm对(5.41±0.17)mm]和收缩末期内径[(5.77±0.15)mm对(5.07±0.19)mm]明显增大,而射血分数明显降低[(18.75±3.03)%)对(23.12±0.70)%],P均<0.01。C1ORF54基因敲除小鼠心肌纤维化程度增高,Ki-67阳性细胞数明显减少。两组小鼠心肌p38/p-P38、STAT3/p-STAT3、β-catenin的蛋白表达水平无统计学差异,C1ORF54基因敲除小鼠p-AKT的蛋白表达水平较野生型小鼠明显降低(P<0.05)。结论:C1ORF54可能通过调控PI3K/AKT信号通路,影响心肌纤维增殖,在心肌梗死后心脏组织修复中发挥重要作用。

Effects of C1ORF54 on cardiac repair after myocardial infarction in mice

Objective:To investigate the effects and mechanisms of C1ORF54 on cardiac repair after myocardial infarction. Methods:Myocardial infarction model was established by ligating left anterior coronary artery in wild-type and C1ORF54 knockout mice.Twenty-one days later,left ventricular size and function were determined by echocardiography,and the degree of myocardial fibrosis was assessed by Masson technique.Myocardial Ki-67 expression was evaluated by immunohistochemistry at the third day after myocardial infarction.The expression of regulatory pathways including p38/p-P38,STAT3/ p-STAT3,β-catenin and p-AKT was quantified by western blot. Results:Twenty-one days after myocardial infarction,despite similar heart rate,the left ventricular end-diastolic[(6.04±0.14)mm vs.(5.41±0.17)mm]and end-systolic diameters[(5.77±0.15)mm vs.(5.07±0.19)mm]were greater,while ejection fraction [(18.75±3.03)% vs.(23.12±0.70)%]was lower in C1ORF54 knockout mice than those in wild-type mice(all P<0.01).The degree of myocardial fibrosis was higher while the number of Ki-67 positive cells was lower in C1ORF54 knockout mice.Although the expression of p38/p-P38,STAT3/p-STAT3,andβ-catenin was similar,the p-AKT phosphorylation of infarct myocardium was considerably reduced in C1ORF54 knockout mice(P<0.05). Conclusions:The present study suggests that C1ORF54 promotes cardiac repair after myocardial infarction through PI3K/AKT signaling pathway.